1. Field of the Invention
The present invention relates generally to a cooling device for cooling a pluggable module, and more particularly to a cooling device for a small form-factor pluggable (SFP) optical transceiver module.
2. Description of the Prior Art
Transceivers are utilized to interconnect circuit cards of communication links and other electronic modules or assemblies. Various international and industry standards define the type of connectors used to connect computers to external communication devices, such as modems, network connectors, and other transceivers. A well-known type of transceiver module known as Gigabit Connector Converter (GBIC) provides a connection between a computer and an Ethernet, Fiber Channel, or another data communication environment.
It is desirable to miniaturize transceivers in order to increase the port density at a network connection (at switch boxes, cabling patch panels, wiring closets, computer I/O, etc.). Small form-factor pluggable transceiver modules, such as 10-gigabit small form-factor pluggable (XFP) transceiver modules, were developed to meet this need. SFP transceivers are substantially less than one half the size of a GBIC transceiver, and transmit data transmission at higher rates, allowing higher aggregated data throughput in a communication system.
Referring to FIG. 8, the well-known pluggable transceiver module usually includes a pluggable component and a frame for accommodating the pluggable component therein. The frame is mounted on a circuit board. When inserted into the frame, the pluggable component will be mechanically and electrically connected with the circuit board.
For the sake of explanation, we will take an SFP transceiver module for example hereafter. Most commonly, the frame of the SFP transceiver module is a metal enclosure with front opening. FIG. 8 shows two sets of pluggable components and frames on a circuit board in which the right pluggable component is in a state before the pluggable component is inserted while the left pluggable component is in a state after the pluggable component is inserted. In operation, when the pluggable components are inserted, the heat generated by these components will be conducted to frame walls firstly, and then released to local air by the frame walls. There are usually some holes on top walls of the frames to improve heat convention and radiation. However, the pluggable component and frame are not well contacted. There is inevitably an air gap between the pluggable component and an inside surface of the frame, which blocks the heat conduction therebetween. Since there is a big thermal resistance for heat dissipation from frame to air, this solution only fits for an SFP transceiver module with small power consumption. With the data transfer rate growing, the power consumption of the pluggable module is increasing. It requires thermal solutions in many systems for such device. Furthermore, the module is pluggable, which requires a flexible cooling solution.
Referring to FIG. 9, a Taiwan Patent TW309316U, titled “SFP cage with heat sink”, provides an improved thermal solution for an SFP transceiver module. Said module includes a pluggable component and a frame with top, bottom, rear and side walls. The top wall is centrally opened. A heat sink is mounted on the frame and extends through an opening on top wall of the frame. The heat sink is positioned to make a direct contact with the pluggable component. A clip is mounted over the heat sink and engaged with tabs on the side walls of the frame to retain it. Such an arrangement of the heat sink helps the heat generated from the pluggable component to release. Since the size of the heat sink is usually limited, under the condition of multiple pluggable modules assembling in one system, it usually requires an additional forced convection unit to enhance the heat dissipation efficiency, thus making the system relatively complex.
Accordingly, there is a need for an SFP transceiver module having a reinforced and compact cooling structure that improves the heat dissipation efficiency.